Display systems of the type used, for example, in signs and placards, posters, pictures, stickers, illuminated and reflective signs, are produced by a wide variety of techniques. A typical display system comprises a laminate of an optically transparent protective cover surface and a sheet of paper carrying the required information printed thereon. In general the printing process is expensive, particularly where colour printing is required, and for outdoor applications the paper must be protected against ingress of water.
It is known to laminate the printed paper sheet to the optically transparent cover surface using an optically transparent adhesive, and if necessary to apply a protective backing surface which may also be adhered to the paper.
Such laminates are widely used for advertising and display purposes, but because of the printing process are relatively expensive, particularly when only small numbers of prints are required.
Attempts have been made to produce laminates for advertising and display purposes by the use of heat transfer processes, but these are also relatively expensive and of limited application. Photographic processes have also been used, but only to a limited extent again because of the high costs involved
EP-A-0424131 discloses a process for the electrophotographic deposition of an image on a strippable resin layer formed on a carrier sheet, and subsequent lamination of the stripped, imaged layer with a protective plastics layer. However, the process employed is for the production of large scale vehicle signs and is not concerned with the quality of the final image.
There is therefore a need for a laminate comprising a protective optically transparent cover surface and a sheet carrying information to be displayed, which is both versatile and can be inexpensively produced in small or large quantities on relatively inexpensive equipment. More importantly, there is a need for high quality imaging which is still inexpensive but which produces images which are long-lasting, weather-resistant and of museum-quality, that is to say, an accurate an photographic-type reproduction of the original.